Three-dimensional printing apparatus

ABSTRACT

A three-dimensional printing apparatus is provided, including a container, a display, a control unit and an optical film. The container contains a photosensitive material. The display has a plurality of display units. Each of the display units is capable of emitting a light beam. The control unit is capable of controlling the display units. The optical film is capable of projecting the light beams emitted from the display units onto the photosensitive material, forming a plurality of projected patterns. An arranging sequence and an arranging direction of the projected patterns are substantially the same as an arranging sequence and an arranging direction of the display units.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Reissue Application of U.S. Pat. No. 8,985,989issued on Mar. 24, 2015, application Ser. No. 13/663,484, filed on Oct.30, 2012, which claims the priority benefit of Taiwan application serialno. 101115784, filed on May 3, 2012. The entirety of each of theabove-mentioned patent application applications is hereby incorporatedby reference herein and made a part of this specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a printing apparatus, more particularly, to athree-dimensional printing apparatus.

2. Description of Related Art

Rapid Prototyping (RP) is a new prototype manufacturing technologydeveloped in the mid-80s. Rapid Prototyping has combined technologiessuch as mechanical engineering, Computer-aided design (CAD), digitalcontrol technology, laser technology and material science, allowing thedesign concept to be automatically, directly, quickly and accuratelytransformed into a prototype with certain functionalities ormanufacturing parts, as a result, assessment, modification andfunctionalities test to the design concept can be quickly performed,thereby remarkably reducing the developing and manufacturing process ofthe product. With advantages like agility, adaptable for all sorts offorms, high flexibility and high integration, it is widely applied indifferent technical fields such as mechanical, motor vehicle,electronic, communication and aerospace technology. During an initialstage of the development, a CAD file of required drawings is designed,an original model is manufactured before the actual production, and usedfor design confirmation, product modification, functionality test andmolding process, such model is known as the prototype.

Different prototyping materials are used according to differentprototyping technologies, in which their prototyping principle andsystem features are also different from each other. For example, stereolithography apparatus (SLA) is the first commercialized system withbiggest share of market. The processing principle thereof is consistedof the following steps: scanning the liquid photosensitive polymer byusing HeCd laser or Argon laser; thereby generating a polymerized curedthin-film; next, bringing the lifting table down and then up again;applying another layer of polymer resin on the surface of the desiredprocessing area; scraping off the liquid surface with a scraper untilthe surface is horizontal; scanning the surface with laser so theprocessing area is closely combined with the upper layer thereof;repeating above steps until the desired three-dimensional work piece isgenerated. In addition, the image-forming system using SLA technology iseither the laser scanning system or the light projector, since thehardware of the system is complex and large in size, and theimage-forming distance for the laser scanning system or the projectorneeds to be included in the machine, the overall size of the such systemcannot be miniaturized.

Regarding related art of the prototyping technology, U.S. Pat. No.5,980,813 has disclosed a rapid prototyping method using multilayermaterials. US Patent Publication No. 20100262272 has also disclosed anapparatus of manufacturing three-dimensional object by using curablematerials.

SUMMARY OF THE INVENTION

A three-dimensional printing apparatus is provided, and thethree-dimensional printing apparatus has structure to help reducingoverall size of the three-dimensional printing apparatus.

Other objects and advantages of the invention can be further illustratedby the technical features broadly embodied and described as follows.

A three-dimensional printing apparatus is provided according to anembodiment of the invention. The three-dimensional printing apparatusincludes a container, a display, a control unit and an optical film. Thecontainer contains a photosensitive material. The display has aplurality of display units, and each of the display units is capable ofemitting a light beam. The control unit is connected to the display, forcontrolling the display units. The optical film is disposed between thedisplay and the container, for projecting the light beams emitted fromthe display units onto the photosensitive material, so as to form aplurality of projected patterns. An arranging sequence and an arrangingdirection of the projected patterns are substantially the same as anarranging sequence and an arranging direction of the display units.

In an embodiment of the invention, the container has a bottom, disposedbetween the display and the photosensitive material, and the bottom is alight-transparent bottom, the bottom of the container has an uppersurface facing the photosensitive material.

In an embodiment of the invention, a distance between the display andthe upper surface of the container is less than or equal to 3 cm.

In an embodiment of the invention, the three-dimensional printingapparatus further comprises a work platform, dipped into thephotosensitive material, capable of moving relatively with thecontainer. The work platform has a work surface, wherein the workplatform is controlled by the control unit, the control unit commandsthe display to display a first image during a first time and locates thework surface to a first location. The light beams emitted from thedisplay units corresponding to the first image are projected onto afirst layer of the photosensitive material between the work surface andthe upper surface through the optical film, so as to cure the firstlayer of the photosensitive material to form a first cured layer. Andthe control unit commands the display to display a second image during asecond time and locates the work surface to the second location. Thelight beams emitted from the display units corresponding to the secondimage are projected to a second layer of the photosensitive materialbetween the first cured layer and the upper surface through the opticalfilm, so as to cure the second layer of the photosensitive material toform a second cured layer.

In an embodiment of the invention, the work surface faces the bottom.The second cured layer is located between the first cured layer and thebottom, and the first location is located between the bottom and thesecond location.

In an embodiment of the invention, the optical film comprises aplurality of optical structures, and each of the optical structures isaligned with at least one of the display units.

In an embodiment of the invention, each of the optical structures is alens, and each of the lenses is aligned with one of the display units.

In an embodiment of the invention, each of the optical structures is acylindrical lens, and each of the cylindrical lenses is aligned with arow of the display units.

In an embodiment of the invention, an image of the display units isprojected on the photosensitive material to form the projected patternsby the optical structures.

In an embodiment of the invention, each of the display units comprisesat least a pixel. A size of each of the optical structures is an integertimes a size of the pixel of the corresponding display unit.

In an embodiment of the invention, the optical film comprises aplurality of optical structures, and each of the display units isaligned with some of the optical structures. A size of each of thedisplay units is an integer times a size of the corresponding opticalstructure.

In an embodiment of the invention, the optical film comprises aplurality of optical structures, and each of the optical structures is apyramidal prism or a triangular-shaped prism.

In an embodiment of the invention, the optical film is a Fresnel lens,diffusing film or a privacy filter.

In an embodiment of the invention, the light beams emitted from thedisplay units are visible light.

In an embodiment of the invention, the optical film may be a singlelayer film or a multilayer film.

Based on above, the three-dimensional printing apparatus according tothe embodiment of the invention projects the display units of thedisplay onto the photosensitive material through the optical film, andthe arranging sequence and the arranging direction of the projectedpatterns are substantially the same as the arranging sequence andarranging direction of the display units. As a result, a distancebetween the display and the photosensitive material may be reduced,thereby reducing a size of the three-dimensional printing apparatus, andproviding good effect of three-dimensional printing.

Other objectives, features and advantages of the present invention willbe further understood from the further technological features disclosedby the embodiments of the present invention wherein there are shown anddescribed preferred embodiments of this invention, simply by way ofillustration of modes best suited to carry out the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A, FIG. 1B and FIG. 1C are schematic views of operations in athree-dimensional printing apparatus according an embodiment of theinvention.

FIG. 2 is a schematic view of a plurality of display units of a display.

FIG. 3A illustrates a corresponding relationship between the displayunits of the display and a plurality of optical structures of an opticalfilm in a first embodiment of the invention.

FIG. 3B is a side view of FIG. 3A.

FIG. 4A illustrates a corresponding relationship between the displayunits of the display and the optical film in a second embodiment of theinvention.

FIG. 4B is a side view of FIG. 4A.

FIG. 5A illustrates a corresponding relationship between the displayunits of the display and the optical structures of the optical film in athird embodiment of the invention.

FIG. 5B is a side view of FIG. 5A.

FIG. 6A illustrates a corresponding relationship between the displayunits of the display and the optical structures of the optical film in afourth embodiment of the invention.

FIG. 6B is a side view of FIG. 6A.

FIG. 7A illustrates a corresponding relationship between the displayunits of the display and the optical structures of the optical film in afifth embodiment of the invention.

FIG. 7B is a side view of FIG. 7A.

FIG. 8 illustrates a corresponding relationship between the displayunits of the display and the optical structures of the optical film in asixth embodiment of the invention.

DESCRIPTION OF THE EMBODIMENTS

In the following detailed description of the preferred embodiments,reference is made to the accompanying drawings which form a part hereof,and in which are shown by way of illustration specific embodiments inwhich the invention may be practiced. In this regard, directionalterminology, such as “top,” “bottom,” “front,” “back,” etc., is usedwith reference to the orientation of the Figure(s) being described. Thecomponents of the present invention can be positioned in a number ofdifferent orientations. As such, the directional terminology is used forpurposes of illustration and is in no way limiting. On the other hand,the drawings are only schematic and the sizes of components may beexaggerated for clarity. It is to be understood that other embodimentsmay be utilized and structural changes may be made without departingfrom the scope of the present invention. Also, it is to be understoodthat the phraseology and terminology used herein are for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having” and variations thereof herein ismeant to encompass the items listed thereafter and equivalents thereofas well as additional items. Unless limited otherwise, the terms“connected,” “coupled,” and “mounted” and variations thereof herein areused broadly and encompass direct and indirect connections, couplings,and mountings. Similarly, the terms “facing,” “faces” and variationsthereof herein are used broadly and encompass direct and indirectfacing, and “adjacent to” and variations thereof herein are used broadlyand encompass directly and indirectly “adjacent to”. Therefore, thedescription of “A” component facing “B” component herein may contain thesituations that “A” component directly faces “B” component or one ormore additional components are between “A” component and “B” component.Also, the description of “A” component “adjacent to” “B” componentherein may contain the situations that “A” component is directly“adjacent to” “B” component or one or more additional components arebetween “A” component and “B” component. Accordingly, the drawings anddescriptions will be regarded as illustrative in nature and not asrestrictive.

FIG. 1A, FIG. 1B and FIG. 1C are schematic views of operations in thethree-dimensional printing apparatus according an embodiment of theinvention. A three-dimensional printing apparatus 100 includes acontainer 110, a display 120 and an optical film 130. The container 110contains a photosensitive material 112, and the photosensitive material112 may be a fluid material or a semi-fluid material. The display 120has a plurality of display units 122, and each of the display units 122is capable of emitting a light beam L. The optical film 130 is capableof projecting the light beams L emitted from the display units 122 ontothe photosensitive material 112, forming a plurality of projectedpatterns on the photosensitive material 112. The optical film 130 may bea single layer film or a stacked multilayer film.

Specifically, in the present embodiment, the display 120 is disposedunder a bottom 114 of the container 110, and the optical film 130 isdisposed between the display 120 and the bottom 114 of the container110. In addition, since the bottom 114 of the container 110 is alight-transparent bottom, after the light beams L emitted from thedisplay units 122 pass through the optical film 130, the light beams Lmay go through the bottom 114 and project the projected patterns on thephotosensitive material 112, thereby causing a chemical reaction (suchas curing or hardening) with the photosensitive material 112. Anarranging sequence and an arranging direction of the projected patternson the photosensitive material 112 are substantially the same as anarranging sequence and an arranging direction of the display units 122on the display 120. For example, referring to FIG. 1A, the display units122A, 122B and 122C respectively project the projected patterns to aplurality of locations a, b and c on the photosensitive material 112.The arranging sequence and the arranging direction of the locations a, band c of the projected patterns on the photosensitive material 112 aresubstantially the same as the arranging sequence and arranging directionof the display units 122A, 122B and 122C on the display 120. That is,the display units 122A, 122B and 122C are arranged from left to right,and the locations a, b and c respectively correspond to the displayunits 122A, 122B and 122C and are also arranged from left to right.Similarly, viewing along a direction perpendicular to the paper plane ofFIG. 1A, the arranging sequence and the arranging direction of theprojected patterns on the photosensitive material 112 are the same asthe arranging sequence and the arranging direction of the display units122 on the display 120, for example, both are arranged in the directiontoward the paper plane of FIG. 1A. In the embodiment, the locations ofthe display units 122 on the display 120 correspond to the projectedpatterns on the photosensitive material 112 in a one-to-one manner. As aresult, an image displayed by the entire display units 122 may be formedcorrespondingly on the photosensitive material 112. Referring again toFIG. 1A to FIG. 1C, in some embodiments, an optical assembly configuredfor the three-dimensional printing apparatus 100 can be formed byincluding the container 110 and the display 120 therein.

It is noted that, in the three-dimensional printing apparatus 100 of theembodiment, the image displayed on the display 120 is divided intomultiple display units 122 for displaying, and the light beams L of thedisplay units 122 corresponding to the image are projected onto thephotosensitive material 112 to form the projected patterns through theoptical film 130 in the one-to-one manner. The arranging sequence andthe arranging direction of the projected patterns on the photosensitivematerial 112 are substantially the same as the arranging sequence andthe arranging direction of the display units 122 on the display 120. Inthe present embodiment, a projection system configured for thethree-dimensional printing apparatus 100 can be formed by including thecontainer 110 and the display 120 comprising the display units 122therein. Comparatively, a conventional three-dimensional device with theprojection lens projects the image of the display 120 by using wholesurface image-forming method via the projection lens, forming the imageon the photosensitive material 112. Based on the image-formingprinciple, the image formed on the photosensitive material 112 is a 180degree reversed image. Therefore, design of an image-forming distance isnecessary in order to meet the image-forming requirement, therebyincreasing the size of the printing device.

In the embodiment, the image displayed on the display 120 is dividedinto multiple display units 122, and the light beams L of the displayunits 122 of the display 120 corresponding to the image are projected onthe photosensitive material 112 to form the projected patterns throughthe optical film 130 in the one-to-one manner. Since a size of eachdisplay unit 122 is smaller than the entire image, the projectingdistance between the display units 122 and the photosensitive material112 may be reduced. As a result, a required distance between the display120 and the photosensitive material 112 may be reduced, and the size ofthe three-dimensional printing apparatus 100 may also be reduced. Forexample, in the embodiment, a distance between the display 120 and anupper surface 114a of the bottom 114 of the container 110 is less thanor equal to 3 cm. On the other hand, the display 120 of the embodimentmay be a liquid crystal display. Therefore, a light source of thedisplay 120 provided for projecting may be a visible light. However, aninvisible light (such as UV light) source for curing or hardening thephotosensitive material 112 may also be used.

Referring to FIG. 1A, in particularly, the three-dimensional apparatus100 further includes a work platform 140 and a control unit 150. Thework platform 140 is dipped into the photosensitive material 112 andcapable of moving with respect to the container 110, wherein the workplatform 140 has a work surface 140a facing the bottom 114 of thecontainer 110. The control unit 150 is coupled with the work platform140 and the display 120, for controlling the work platform 140 and thedisplay unit 122. In the embodiment, the work platform 140 is capable ofrelatively moving from top to bottom of the container 110 or from bottomto top of the container 110.

Next, referring to FIG. 1A, FIG. 1B, and FIG. 1C in sequence. In FIG.1A, the control unit 150 commands the display 120 to display a firstimage during a first time, and the first image is divided into aplurality of corresponding display units 122, and the work surface 140ais located at a first location (the location as shown in FIG. 1A). Here,the light beams L emitted from the display units 122 corresponding tothe first image are projected to a layer of the photosensitive material112 between the work surface 140a of the work platform 140 and the uppersurface 114a of the bottom 114 through the optical film 130, such that afirst cured layer S1 is formed by curing the layer of the photosensitivematerial 112 between the work surface 140a and the upper surface 114aand corresponds to the first image. Next, in FIG. 1B, the work surface140a moves to be located at a second location (the location as shown inFIG. 1B) by the control unit 150 during a second time. Here, thephotosensitive material 112 in the container 110 is filled between thefirst cured layer S1 and the upper surface 114a, the control unit 150commands the display 120 to display a second image, and the second imageis divided into a plurality of corresponding display units 122. Thelight beams L emitted from the display units 122 corresponding to thesecond image are projected to a layer of the photosensitive material 112between the first cured layer S1 and the upper surface 114a through theoptical film 130, such that a second cured layer S2 is formed by curingthe layer of the photosensitive material 112 between the first curedlayer S1 and the upper surface 114a and corresponds to the second image.Subsequently, in FIG. 1C, the work surface 140a moves to be located at aN^(th) location (the location as shown in FIG. 1C) by the control unit150. The control unit 150 commands the display 120 to display an N^(th)image during an N^(th) time, the N^(th) image is divided into aplurality of corresponding display units 122. The light beams Lcorresponding to the N^(th) image are projected to a layer of thephotosensitive material 112 between an N−1^(th) cured layer SN−1 and theupper surface 114a through the optical film 130, so that an N^(th) curedlayer SN is formed by curing the layer of the photosensitive material112 between an N−1^(th) cured layer SN−1 and the upper surface 114a andcorresponds to the N^(th) image. In the embodiment, N, for example, is apositive integer larger than or equal to 3.

Regarding the embodiment, the work surface 140a faces the upper surface114a of the bottom 114, the second cured layer S2 is located between thefirst cured layer S1 and the upper surface 114a of the bottom 114, andthe first location is located between the bottom 114 and the secondlocation. More specifically, a slicing process may be performed on thethree-dimensional object, so as to divide an object into multilayerimage data. The control unit 150 commands the corresponding displayunits 122 to display the first layer image of the object during thefirst time. Next, the corresponding display units 122 are commanded todisplay the second layer image of the object during the second time.After repeating said process for a number of times, the images ofdifferent layers are sequentially projected to the corresponding layersof photo sensitive material 112 through the optical film 130, so thatthe corresponding layers of the photosensitive material 112 are cured inrespond to each different layer of images, such that a three-dimensionalobject is formed in a layer-by-layer manner.

In the embodiment, the display 120 is disposed under the bottom 114 ofthe container 110, so that the light beams L of the display units 122may be emitted from bottom to top onto the photosensitive material 112above the upper surface 114a of the bottom 114. However, the inventionis not limited thereto. In other embodiments, the display 120 may alsobe disposed on a top of the container 110 (not illustrated), so that thelight beams L of the display units 122 may be emitted from top to bottomonto the photosensitive material 112.

FIG. 2 is a schematic view of the plurality of display units of thedisplay. Referring to FIG. 2, in the three-dimensional printingapparatus 100, the display 120 may be a liquid crystal display panel,and the display unit 122 may include at least one pixel 122a in theliquid crystal display panel. For example, in FIG. 2, the display units122 are composed by nine pixels 122a. The number of the pixels 122aincluded in the display units 122 may be adjusted according to therequired resolution of the image. On the other hand, the conventionalthree-dimensional technology usually uses a display with color filter.The three-dimensional printing apparatus 100 according to an embodimentof the invention may use a display 120 without color filter, each of thesub-pixels corresponding to filters of different color in the originaldisplay may now be referred to as one single pixel, such that theresolution of the display 120 may be improved, thereby allowing thethree-dimensional printing technology in providing a higher resolution.

In the embodiment, the optical film 130 includes a plurality of opticalstructures 132, for projecting the light beams L emitted from thedisplay unit 122 onto the photosensitive material 112. Severalpreferable embodiments are provided below to further illustrate therelative relation between the display unit 122 and the optical film 130.

FIG. 3A illustrates a corresponding relationship between the displayunits of the display and the optical structures of the optical film in afirst embodiment of the invention. FIG. 3A is a top view illustratingthe overlapping of the display 120 and an optical film 130A, wherein theportion with dotted line surrounded represents the display 120, and theportion with full line surrounded represents the optical film 130A. FIG.3B is a side view of FIG. 3A.

Referring to FIG. 3A and FIG. 3B together. In the embodiment, theoptical film 130A has a plurality of optical structures 132A, whereineach optical structure 132A is a lens (such as lens having bent surfaceon both two directions that are perpendicular to each other), a size ofeach optical structure 132A is substantially equal to the size of eachdisplay unit 122.

FIG. 4A illustrates a corresponding relationship between the displayunits of the display and the optical structures of the optical film in asecond embodiment of the invention. FIG. 4B is a side view of FIG. 4A.Each optical structure 132B of the optical film 130B of the embodimentis similar to the optical structure 132A shown in the FIG. 3A, namely,the lens. However, a size of each optical structure 132B issubstantially smaller than the size of the display unit 122.

FIG. 5A illustrates a corresponding relationship between the displayunits of the display and the optical structures of the optical film in athird embodiment of the invention. FIG. 5B is a side view of FIG. 5A. Inthe embodiment, each optical structure 132C on the optical film 130C isa cylindrical lens, and a width of each optical structure 132C issubstantially equal to the width of the display unit 122.

According to the embodiments in FIG. 3A, FIG. 4A and FIG. 5A, an imageof the display units 122 is formed on the photosensitive material 112through the lens or the cylindrical lens. Therefore, each of the opticalstructures 132A, 132B and 132C may be adjusted, for aligning with atleast one display unit 122. For example, in FIG. 3A, each lens (theoptical structure 132A) is aligned with one corresponding display unit122. In another embodiment, each of the display unit 122 is aligned witha plurality of optical structures. For example, in FIG. 4A, each of thedisplay units 122 is align with four lenses (the optical structures132B). When one display unit 122 includes a plurality of pixels 122a(referring to FIG. 2), each lens is aligned with the plurality of pixels122a, and when one display unit 122 includes one pixel 122a, each lensis aligned with one pixel 122a. In other words, in FIG. 3A, the size ofeach optical structure 132A may be an integral times the size of thepixel 122a of the corresponding display unit 122 (referring to FIG. 2).Whereas in FIG. 4A, the size of each display unit 122 is an integraltimes the size of the corresponding optical structure 132B. In FIG. 5A,each cylindrical lens (the optical structure 132C) is aligned with a rowof display units 122. Since the size of each display unit 122 is smallerthan the size of the entire image displayed by the display 120, theimage-forming distance for projecting the image of the display units 122respectively onto the photosensitive material 112 by using the opticalstructures 132 (such as the plurality of lenses or cylindrical lenses)may be smaller than the image-forming distance for projecting the entireimage onto the photosensitive material 112 by using whole surfaceimage-forming method. Therefore, the overall size of thethree-dimensional printing apparatus 100 may be effectively reduced.

FIG. 6A illustrates a corresponding relationship between the displayunits of the display and the optical structures of the optical film in afourth embodiment of the invention. FIG. 6B is a side view of FIG. 6A.In the embodiment, each optical structure 132D of the optical film 130Dis a triangular-shaped prism, and a width of each optical structure 132Dis substantially equal to the width of the display unit 122.

FIG. 7A illustrates a corresponding relationship between the displayunits of the display and the optical structures of the optical film in afifth embodiment of the invention. FIG. 7B is a side view of FIG. 7A. Inthe embodiment, each optical structure 132E of the optical film 130E isa pyramidal prism, and a size of each optical structure 132E is equal tothe size of each display unit 122.

However, in other embodiments, the size of the triangular-shaped prismor the pyramidal prism may not be an integer times the display unit 122,and the location of the triangular-shaped prism or the pyramidal prismmay not have corresponding relationship with the location of the displayunit 122, both are also possible.

FIG. 8 illustrates a corresponding relationship between the displayunits of the display and the optical structures of the optical film in asixth embodiment of the invention. In the embodiment, the optical film130F is a diffusing film, and optical structures 132F of the opticalfilm 130F are provided for converging the light beams L, whereas in theother embodiments, the optical film 130F may also be a Fresnel lens or aprivacy filter.

In the embodiments of FIG. 6A and FIG. 7A, the method for projecting thedisplay units 122 on the photosensitive material 112 is tended to use aprojection method. Therefore, the locations of each triangular-shapedprism (the optical structure 132D) and each pyramidal prism (the opticalstructure 132E) may not have corresponding relationship with thelocations of the display units 122. However, the light beams L emittedfrom the corresponding display units 122 may be converged onto thephotosensitive material 112 (as shown in FIG. 1A, FIG. 1B and FIG. 1C).Similarly, the optical film 130F (such as a Fresnel lens or a privacyfilter) shown in FIG. 8 is also capable of converging the light beams Lemitted from the display units 122. In addition, when the light beams Lemitted from the display 120 are converged more, the light beams L ofthe display units 122 may still be projected on the photosensitivematerial 122 (as shown in FIG. 1A, FIG. 1B and FIG. 1C) when the opticalfilm 130F is the diffusing film.

Based on above, the three-dimensional printing apparatus according tothe embodiment of the invention projects the display units of thedisplay onto the photosensitive material through the optical film, andthe arranging sequence and the arranging direction of the projectedpatterns are substantially the same as the arranging sequence andarranging direction of the display units. As a result, the distancebetween the display and the photosensitive material may be reduced,thereby reducing the size of the three-dimensional printing apparatus,and providing good effect of three-dimensional printing.

The foregoing description of the preferred embodiments of the inventionhas been presented for purposes of illustration and description. It isnot intended to be exhaustive or to limit the invention to the preciseform or to exemplary embodiments disclosed. Accordingly, the foregoingdescription should be regarded as illustrative rather than restrictive.Obviously, many modifications and variations will be apparent topractitioners skilled in this art. The embodiments are chosen anddescribed in order to best explain the principles of the invention andits best mode practical application, thereby to enable persons skilledin the art to understand the invention for various embodiments and withvarious modifications as are suited to the particular use orimplementation contemplated. It is intended that the scope of theinvention be defined by the claims appended hereto and their equivalentsin which all terms are meant in their broadest reasonable sense unlessotherwise indicated. Therefore, the term “the invention”, “the presentinvention” or the like does not necessarily limit the claim scope to aspecific embodiment, and the reference to particularly preferredexemplary embodiments of the invention does not imply a limitation onthe invention, and no such limitation is to be inferred. The inventionis limited only by the spirit and scope of the appended claims. Theabstract of the disclosure is provided to comply with the rulesrequiring an abstract, which will allow a searcher to quickly ascertainthe subject matter of the technical disclosure of any patent issued fromthis disclosure. It is submitted with the understanding that it will notbe used to interpret or limit the scope or meaning of the claims. Anyadvantages and benefits described may not apply to all embodiments ofthe invention. It should be appreciated that variations may be made inthe embodiments described by persons skilled in the art withoutdeparting from the scope of the present invention as defined by thefollowing claims. Moreover, no element and component in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element or component is explicitly recited in the followingclaims. In addition, the terms such as “first”, “second” as recited inthe specification or the claims are used to give the elements names ordistinguish different embodiments or scopes, but not to limit themaximum number or the minimum number of the elements.

What is claimed is:
 1. A three-dimensional printing apparatus,comprising: a container, containing a photosensitive material; adisplay, having a plurality of display units, each of the display unitsbeing capable of emitting a light beam; a control unit, connected to thedisplay and controlling the display units of the display; and an opticalfilm, disposed between the display and the container, the optical filmcomprising a plurality of optical structures folined thereon andarranged in a direction perpendicular to a transmission direction of thelight beams, and the optical structures respectively projecting thelight beams emitted from the corresponding display units onto thephotosensitive material to a plurality of projected patterns, wherein anarranging sequence and an arranging direction of the projected patternsare substantially the same as an arranging sequence and an arrangingdirection of the display units, and a dimension of each of the projectedpatterns is substantially equal to a dimension of each of the displayunits, so that the projected patterns are formed as not overlapping, anda distance between the display and the upper surface of the container isless than or equal to 3 cm.
 2. The three-dimensional printing apparatusof claim 1, wherein the container has a bottom, disposed between thedisplay and the photosensitive material, and the bottom is alight-transparent bottom, the bottom of the container has an uppersurface facing the photosensitive material.
 3. The three-dimensionalprinting apparatus of claim 2, wherein a distance between the displayand the upper surface of the container is less than or equal to 3 cm. 4.The three-dimensional printing apparatus of claim 2, further comprising:a work platform, dipped into the photosensitive material, capable ofmoving relatively with the container, wherein the work platform has awork surface; wherein the work platform is controlled by the controlunit, the control unit commands the display to display a first imageduring a first time and locates the work surface to a first location,the light beams emitted from the display units corresponding to thefirst image are projected onto a first layer of the photosensitivematerial between the work surface and the upper surface through theoptical film, so as to cure the first layer of the photosensitivematerial to form a first cured layer, and the control unit commands thedisplay to display a second image during a second time and locates thework surface to the second location, the light beams emitted from thedisplay units corresponding to the second image are projected to asecond layer of the photosensitive material between the first curedlayer and the upper surface through the optical film, so as to cure thesecond layer of the photosensitive material to form a second curedlayer.
 5. The three-dimensional printing apparatus of claim 4, whereinthe work surface faces the bottom, the second cured layer is locatedbetween the first cured layer and the bottom, and the first location islocated between the bottom and the second location.
 6. Thethree-dimensional printing apparatus of claim 1, wherein each of theoptical structures is aligned with at least one of the display units. 7.The three-dimensional printing apparatus of claim 6, wherein each of theoptical structures is a lens, and each of the lenses is aligned with oneof the display units.
 8. The three-dimensional printing apparatus ofclaim 6, wherein each of the optical structures is a cylindrical lens,and each of the cylindrical lenses is aligned with a row of the displayunits.
 9. The three-dimensional printing apparatus of claim 6, whereinan image of the display units is projected on the photosensitivematerial to form the projected patterns by the optical structures. 10.The three-dimensional printing apparatus of claim 6, wherein each of thedisplay units comprises at least a pixel.
 11. The three-dimensionalprinting apparatus of claim 10, wherein a size of each of the opticalstructures is an integer times a size of the pixel of the correspondingdisplay unit.
 12. The three-dimensional printing apparatus of claim 1,wherein each of the display units is aligned with some of the opticalstructures.
 13. The three-dimensional printing apparatus of claim 12,wherein a size of each of the display units is an integer times a sizeof the corresponding optical structure.
 14. The three-dimensionalprinting apparatus of claim 1, wherein each of the optical structures isa pyramidal prism or a triangular-shaped prism.
 15. Thethree-dimensional printing apparatus of claim 1, wherein the light beamsemitted from the display units are visible light.
 16. Thethree-dimensional printing apparatus of claim 1, wherein the opticalfilm may be a single layer film or a multilayer film.
 17. Athree-dimensional printing apparatus, comprising: a container,containing a photosensitive material; a display, having a plurality ofdisplay units, each of the display units being capable of emitting alight beam; a control unit, connected to the display and controlling thedisplay units of the display; and an optical film, disposed between thedisplay and the container and projecting the light beams emitted fromthe display units onto the photosensitive material to form a pluralityof projected patterns, wherein an arranging sequence and an arrangingdirection of the projected patterns are substantially the same as anarranging sequence and an arranging direction of the display units, andthe projected patterns are formed as not overlapping, wherein thecontainer has a bottom, disposed between the display and thephotosensitive material, the bottom is a light-transparent bottom, thebottom of the container has an upper surface facing the photosensitivematerial, and a distance between the display and the upper surface ofthe container is less than or equal to 3 cm.
 18. An optical assembly fora three-dimensional printing apparatus, comprising: a container and adisplay, optically connected with each other, wherein a plurality ofdisplay units are located in the display, and each of the display unitsis capable of emitting a light beam; and the container is disposed abovethe display and comprises a light-transparent bottom being configured toaccommodate a photosensitive material, wherein the light-transparentbottom of the container has an upper surface facing the photosensitivematerial; wherein a distance between the display and an upper surface ofthe transparent bottom of the container is less than or equal to 3 cm.19. The optical assembly of claim 18, wherein the optical assemblyfurther comprises: a control unit, connected to the display andcontrolling the display units of the display; and an optical film,comprising a plurality of optical structures formed thereon and arrangedin a direction perpendicular to a transmission direction of the lightbeams, wherein the optical film is disposed between the display and thecontainer and projects the light beams emitted from the display unitsonto the photosensitive material to form a plurality of projectedpatterns, wherein an arranging sequence and an arranging direction ofthe projected patterns are substantially the same as an arrangingsequence and an arranging direction of the display units, and thethree-dimensional printing apparatus does not have a projection lens,wherein a dimension of each of the projected patterns is substantiallyequal to a dimension of each of the display units, so that the projectedpatterns are formed as not overlapping.
 20. The optical assembly ofclaim 19, further comprising: a work platform, dipped into thephotosensitive material, capable of moving relatively with thecontainer, wherein the work platform has a work surface; wherein thework platform is controlled by the control unit, the control unit isprogrammed to command the display to display a first image during afirst time and locates the work surface to a first location, the lightbeams emitted from the display units corresponding to the first imageare projected onto a first layer of the photosensitive material betweenthe work surface and the upper surface through the optical film, so asto cure the first layer of the photosensitive material to form a firstcured layer, and the control unit commands the display to display asecond image during a second time and locates the work surface to thesecond location, the light beams emitted from the display unitscorresponding to the second image are projected to a second layer of thephotosensitive material between the first cured layer and the uppersurface through the optical film, so as to cure the second layer of thephotosensitive material to form a second cured layer.
 21. The opticalassembly of claim 20, wherein the work surface faces the bottom, thesecond cured layer is located between the first cured layer and thebottom, and the first location is located between the bottom and thesecond location.
 22. The optical assembly of claim 19, wherein theoptical film comprises a plurality of optical structures, and each ofthe optical structures is aligned with at least one of the displayunits.
 23. The optical assembly of claim 22, wherein an image of thedisplay units is projected on the photosensitive material to form theprojected patterns by the optical structures.
 24. The optical assemblyof claim 22, wherein each of the display units comprises at least apixel.
 25. The optical assembly of claim 24, wherein a size of each ofthe optical structures is an integer times a size of the pixel of thecorresponding display unit.
 26. The optical assembly of claim 19,wherein the optical film comprises a plurality of optical structures,and each of the display units is aligned with some of the opticalstructures.
 27. The optical assembly of claim 26, wherein a size of eachof the display units is an integer times a size of the correspondingoptical structure.
 28. The optical assembly of claim 19, wherein theoptical film comprises a plurality of optical structures, and each ofthe optical structures is a lens, a cylindrical lens, a pyramidal prismor a triangular-shaped prism.
 29. The optical assembly of claim 19,wherein the optical film is a Fresnel lens, diffusing film or a privacyfilter.
 30. The optical assembly of claim 18, wherein the light beamsincident on a lower surface of a cured photosensitive material aresubstantially perpendicular to the lower surface of the curedphotosensitive material.
 31. A projection system for a three-dimensionalprinting apparatus, comprising: a display, comprising a plurality ofdisplay units; and a container disposed above the display and comprisinga light-transparent bottom being configured to accommodate aphotosensitive material, wherein the light-transparent bottom of thecontainer has an upper surface facing the photosensitive material,wherein each of the display units is capable of emitting light beams tothe light-transparent bottom, and a distance between the display and ofthe upper surface of the transparent bottom of the container is lessthan or equal to 3 cm.
 32. The projection system of claim 31, whereinthe light beams incident on a lower surface of a cured photosensitivematerial are substantially perpendicular to the lower surface of thecured photosensitive material.
 33. A container for a three-dimensionalprinting apparatus comprising a display and an optical film, comprising:a light-transparent bottom, being configured to accommodate aphotosensitive material, and the light-transparent bottom of thecontainer has an upper surface facing the photosensitive material,wherein a display is disposed under the light-transparent bottom of thecontainer and has a plurality of display units, each of the displayunits being capable of emitting light beams, wherein a single layeroptical film is disposed between the display and the light-transparentbottom of the container, and the single layer optical film comprises aplurality of optical structures formed thereon and is arranged in adirection perpendicular to a transmission direction of the light beams,wherein the light beams emitted from each of the display units passthrough the single layer optical film and subsequently pass through thelight-transparent bottom in a substantially parallel manner to reach alower surface of a cured photosensitive material.
 34. The container ofclaim 33, wherein the single layer optical film projects the light beamsemitted from the display units onto the photosensitive material to forma plurality of projected patterns.
 35. The container of claim 34,wherein the projected patterns are formed as not overlapping.
 36. Thecontainer of claim 34, wherein an arranging sequence and an arrangingdirection of the projected patterns are substantially the same as anarranging sequence and an arranging direction of the display units.